Speed-controlling apparatus for railway-vehicles



L. V. LEWIS,- SPEED CONTROLLING APPARATUS 'FOR RMLWAY VEHICLES.

APPLICATION FILED MR. 12, |915. nenn/ED JAN. l1, |919.

7 SHEETS-SHEET l.

Patented Dec. 16, 1919.

INVENTOR L. V. LEWIS.

SPEED QONTROLLING APPARATUS FOR RAILWAY VEHICLES.

RENEWED IAN. II.19I9.

APPLICATION FILED MAR. l2, IEIIJA Patented Dec. 16, 1919.

7 SHEETS-SHEET 2.

FIG. 2

INVENTOFI WITNESSES @yg/,544@

Ty W YSHEETS-SHEET 3.

Patented Dec. 16, 1919.

L. v. LEW|S. l SPEED CONTROLLING APPARATUS FOR RAILWAY VEHICLES. APPLICATION FILED MAR. I2. |915. RENEWED IAN. II. 1919.

WITNESSE L. V. LEWIS.

SPEED coNTRoLuNG APPARATUS fo RAILWAY vEH|cLs.

L. V. LEWIS.

SPEED CONTROLLING APPARATUS FOR RAILWAY VEHICLES.

APPLICATIDN FILED MAR. I2. I9I5. RENEwED IAN. 11.1919.

1,325,328. Patented Dec. I6, 1919.

7 SHEETS-SHEET 5.

FIG. 6

WITNESSES www@ APPLICATION FILED MAR. I2. 1915. 1,325,828.

L. Vl LEWIS.

SPEED CONIBOLLING vAPPARATUS FOR RAILWAY VEHICLES.

BENI-:WED IAN. II, I9I9.

`Patented Dec. 16, 1919.

YSHEETS-SHEET /xlr-Illllllflnh/ wITNEssEs '/57 INVEN-ron L. V. LEWIS.

SPEED CONTROLLING APPARATUS FOR RAILWAY VEHICLES. APPLICATION FILED MA11.12,1915. RENEWED IAN. 11.1919.

1,325,328. Patented De@.16,1919.

SHEETS-SHEET 6.

travel. complication of the-drawing, l have shown UNITED sans LLOYD V. LEWIS, OF EDG-EWOOD BOROUGH, PENNSYLVANIA, ASSIG-NOR TO THE UNION SWITCH 65 SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A

CORPORATION OF PENNSYLVANIA.

SPEED-CONTROLLING APPARATUS FOR RAILWAY-VEHICLES.

Specification of Letters Patent.

Application led March 12, 1915, Serial No. 13,853. Renewed January 11, 1919. Serial No. 270,749.

To all whom it may concern Be it known that I, LLOYD V. LEWIS, a citizen of the United States, residing at Edgewood Borough, in the county of Allegheny andState of Pennsylvania, have 1nvented certain new and useful Improvements in Speed-Controlling Apparatus for Railway-Vehicles, of which the following is a specification.

My invention relates to speed controlling apparatus for railway vehicles.

I will describe several forms of apparatus embodying my invention and will then point out the novel features thereof in claims.

In the drawings, Figure 1 is a sectional view of part of one form of apparatus embodying my invention. Fig. 2 is a view of another part of one form of apparatus embodying my invention. Figs. 2A, 2B and 2C are views showing part of the apparatus shown in-Fig. 2 in three posit-ions. Fig. 3 is a diagrammatic view of a railway track having applied thereto one form of appara! tus adapted to be used with apparatus embodying my inventidn. Fig. 4 shows a modification of the apparatus shown in Fig. 3. Fig. 5 shows a modificatioon of the apparatus shown in Fig. 2. Fig. 6 is a view, partly diagrammatic, of another form 'of part of the apparatus embodying my invention. Fig. 7 is a diagrammatic view of one form of apparatus embodying my invention applied to a railway track. Fig. 8 is a view showing a modification of the apparatus shown in Fig. 7 Fig. 9 is a vffew showing a modification of the apparatqisshown in Fig. 6.

Similar reference characters refer to similar parts in each of the several views.

Referring rst to Figs. 1 and 2, I have here shown one rail 1 of a railway track on which a ltrain or vehicle V is adapted to In order to prevent unnecessary only one wheel 2 of the train or vehicle, in rolling contact with rail 1. Mounted on the train or vehicle is a casing 3 having a cover plate 8, which casing incloses a centrifugal governor 4, here shown tf.) be of the ordinary liy-ball type, although I do not limit myself to this particular type of governor. Fixed to the shaft 5 of this governor outside ofthe plate 8 is a pinion 5 which is operatively connected to one of the wheelsof train or vehicle V by means of power transmlsslon mechanlsm of any suitable Patented Dec. 16, 19159.-

type, so that the governor is made to rotate v ata speed always proportional to the speed of the train or vehicle. Shaft 5 revolves in a ball bearing 6 located in cover plate 8 and in a ball bearing 7 located in casing 3.

Spider arms v9, Vradially extending from shaft 5 carry at their extremities bell cranks 10 connected to them by means of pins 11. vOne arm 12 of each bell crank carries at its extremity a weight 14. The other arm 13 of each bell crank extends into a slot 15 in the shaft 5. In slot 15' there is located a shaft 16, which carries two annular shoulders 31 and 32, between which the ball shaped ends of arms`13 of bell cranks 10 are inserted. The left end of shaft 16 is carried in a. hole 16a in shaft 5, while the other end of shaft 16 carries the outer ring 17 of a thrust ball bearing 18. The inner ring 19 of this-bearing is fixed to the left extremity of a shaft 20, which is adapted to slide longitudinally in a hole 21 through the head of casing 3. Near its right end shaft 20 is threaded', and screwed over this threaded portion is a nut 22 which is locked in position by a lock is guided near its left extremity by means of a bushing 24e fixed in casing 3. A. stud 33 in shaft 5 is provided as a stop for shaft 16 when the governor d is at rest. When the governor revolves, the centrifugal force of the weights 14 is transmitted by means of bell cranks 10 to act as a thrust on bearing 18. This force is transmitted by shaft 20 and nut 22 to plate 26, which bears against a diaphragm 341. This diapl'iragin will yield unless resisted by an equal or greater force on its other side. 1 set up this resisting force in' the foilowing manner.

An air-tight cylinder 34 closed at one end by means of a head 38 is clamped at its open end to the plate 29, so that the axis of the cylinder coincides with the center line of 'shafts 5 and 20. This cylinder is provided with two pistons 35 and 36, the former of which may be comparatively loose in thel that piston 35 bears against diaphragm 341 and piston 36 bears against cylinder head 38. Air pressure from sources to be pointed out later may be applied through ports 39 and 40. By this means I am enabled to oppose or overcome the force exerted by the action of the centrifuge on diaphragm 341. When no air pressure is applied through ports 39 and 40, the spring alone resists the force due to the centrifuge. When air `pressure is applied through port 40, the piston 36 is pushed up against stop 41, which is cushioned with an annular gasket 42, and thereby spring 37 is compressed, pushing piston 35 against the diaphragm 341 with a. force greater than before. Consequently, the centrifuge 4 may be rotated at a greater speed before it overcomes the force opposing it at the diaphragm. Now, if air at substantially the same pressure is admitted through port 39, piston 3G is forced back against the cylinder head 38, due to the combined action of air pressure plus spring pressure on the left of piston 36. But the force against diaphragm 341 is now greater than before, be-

cause the air pressure acting directly against.

the diaphragm more than offsets the decrease in spring pressure caused by allowing the spring to expand. Consequently the centrifuge 4 maybe rotated at a still greater speed before the force exerted on diaphragm 341 by plate 26 exceeds the force exerted on the diaphragm by the opposing air pressure on piston 35.

ln every case, as long as the force exerted on the diaphragm due to the action of the centrifuge is less than the resisting force, plate 2G is held against face 43 of plate 29. When the centrifugal force transmitted to the diaphragm overcomes the resisting force,

the. diaphragm yields and pushes piston 35v against stop 41.

My device may of course be utilized in many diierent ways to control any desired apparatuson the vehicle; as here shown I use it to control the fluid pressure brakes in the following manner.

An arm 45 fulcrum'ed in casing 3 by a pin 27 is pivoted to shaft 20 by means of a pin 46. rllhe valve stem 49 of a pin valve 44 is operatively attached to arm 45, so that, when the shaft 2O moves to the right, valve 44, which is normally closed by means of a sprlng 48, is opened allowing air pressure to exhaust from pipe 50 through a port 47. Pipe 50 leads to a brake application valve located on the vehicle, which brakeA application valve may be of any suitable type. Suiice it to point out, that when pipe 50 is opened to atmosphere by valve 44 the brakes ofthe vehicle are applied, and the brakes are not released until pressure is restored in pipe 50. When diaphragm 341 yields to the force due to rotation of the centrifuge and thus allows shaft 20 to move to the right, the balls lmedium s Failure o spring 37 causes the vehicle to of the governor y outto a further distance" from the centen of rotation and increase thereby the centrifugal force at the given speed. Consequently, if the force exerted by the springendair pressure remains constant, the speed of thegovernor must decrease to a value less than the speed which caused the application of the brakes, before the force Iexerted by diaphragm 341 again overcomes the force due to the action of the centrifuge.

Since governor 4 always rotates at a 'speed proportional to the speed of the vehicle, the speed of the vehicle is limited by the force which counteracts the force exerted on the diaphragm due to the rotation of the centrifuge. As a concrete example lsuppose that the apparatus is so proportioned that, when the vehicle travels at the rate of 50 miles per hour, and when air at va pressure of lbs. per square inch is admitted through port 39 .to cylinder 34, the forces on the yopposite sides of the diaphragm balance each other. Any increase in speed of the vehicle will augment the force due to the centrifuge, whereby the diaphragm is displaced, valve 44 is opened and the brakes are applied. Due to the increase of moment of the governor balls, the brakes remain applied until the speed ofthe vehicle has been lowered to say 35 miles per hour. Then shaft 20 moves back to the left, valve 44 is closed, pressure builds up in pipe 50 and the brake application valve acts to release the brakes. If air pressure is admitted to-cylinder 34 through port 40, and at the same time the air pressure is allowed to exhaust from the middle compartment of cylinder 34, the force acting` against diaphragm 341 will be less, so that the speed of the vehicle will be limited to a `1105 lower value, say 20 miles per hour. When the air remaining in the cylinder 34 back of piston 36 is exhausted through port 40 the speed of the vehicle will be limited to a still lower value, say 10 miles per hour. 1t will be noted that my device is constructed so as to embody 'the fundamental principles of safety. The application of the brakes is caused by centrifugal force-a force as reliable' and absolute as gravity. Failure of 115 air. pressure in cylinder 34 causes either a ed limit or a low speed limit.

come tol a stand-still.

For the control of air pressure in cylin- 12o der 34 any convenient apparatus may. be used. ln Fig. 2 I have shown one form of such control apparatus, which is operatively connected by pipes and 121 withthe apparatus described above.l ln Fig-'2 l `haveshovvn four cylinders,

51, 52, 53 and'54, the axes of which are oolinear. Cylinder 52 is of larger diameter than cylinder 51'; and cylinders 53 and 54, both of the same diameter, are larger in 130 ton 62 to the right. Upon cylinder 51 arel vmounted two double pin valves 68 and 69 when piston 110 is in the extreme right end of its stroke,'an annular projection 139 on piston 110 seals against a gasket 140 preventing the escape of air through port 128 to cylinder 53. A slide valve 56, operatively connected to piston 110, is movable in suitable guides vin cylinder 51.' vThis slide valve controls ports 57, 58, 59, and 125 of cylinder 51 as will bev explained hereinafter.

.Air is admitted to cylinder 51. through a port 63 and a pipe 621 from a sourcezot approximately constant pressure shown as main reservoir 61. Cylinder Y53 contains a piston 62 movable vthrough a distance marked c. `In the position in which the iston is shown in F i 2 leakage of air -rom cylinder 53 past plston 62 is prevented by a gasket 64. When piston 62 is moved to the left throughl the distance 0, piston rod 66 pushes piston 110 and slide valve 56 through the same distance.- But, when the piston is moved from left to right due to a decrease in theair pressure on the right `hand face ofpiston 62 the slide valve 56 .and piston 110 do not follow, since piston .rod 66 is not connected to piston 110. Cylinder 54 which is shorter than cylinder 53 contains a piston 631 which can move through a shorter distance indicated by i) on the drawing. Piston rod 67 is not connected with piston 62, so that although iston 631 can move piston 62 to the eft through a distance 5,, it cannot move pisthe lower valves 70 and 71 of which are held normally closed by meansy of springs 82 "and 83 respectively, and the upper valves 72 and v73 of which are heldnormally open by the same means. 1V alve stems 7 4 and. 75 are attached to rods 76 and 77, the upper ends of which are attached to armatures 78 and 79 of electromagnets 80 and 8,1. When these electromagnets yare energized they attract their armatures, y thus opening the lower valves 70 and 71 and closing the upper valves 72 and 73. 4Double pin valve 68, when actuated by magnet 80 allows air to pass from cylinder 51 through a port 84, valve 70, a A passage 86, a ball check valve 88,v a pipe 90 and a port 92 into cylinder 54. Double pin valve 69, when actuated by magnet ,81 admits air f'Ifom cylinder '51 through a port 85, a valve 71, aA passage 87, a ball check valve 89, a Vpipe 91 and a port 93 into cylin- `der 53.

The energizing circuits o f magnets 80 and 81 are controlled by contact shoes'94 and 95 respectively. These contact shoes are rigidly attached to and electricall plungers 96 and 97, capagle of reciprocation in the guides 98 and 99 respectively.

Springs 100 and 101 are provided to biasv the plungers to the lower extreme position. Plunger 97 is provided with a projecting trip 4102', which is adapted to strike the valve .stem 104 of a valve 103, after plunger 97 has completed part of its upward stroke.

insulated from' Valve 103 is normally held closed by a spring 105. When open, it permits air to pipe 107 through a port 106 to Y flow from a atmosphere.-

Contact' shoes 94 and 95 are adapted. to engage ramp rails 108 and 109 respectively, located in the trackway. and ramp rail 108 are not in the same vertical plane as contact shoe 95 and ramp rail l109. For exam le,the' former maybe located in a vertlcal plane midway'between the track rails, and the latter in a vertical plane outside the track rail.' Ramp rails 108 and 109 may be energized 4by batteries K and K,.thr`ough circuit controllers P and P', as will be explained in the description vofFigs. 3 and 4.

` Whenthe parts of the apparatus on the car are in the positions shown in Figs. 1 and 2, which l will term the slow-speed position, cylinders 51 and 52 are under pressure of air from reservoir 61. The slide valve 56 is held at the right end of its stroke by air pressure in cylinder 51. acting on pis# ton 110, the opposite side of piston 110 being connected to atmosphere throughport 55, pipe 126, port 58 of cylinder 51, cavity 119 of slide valve 56, and port 57 of cylinder 51. ln this position, the chamber between pistons 35 and' 36 of cylinder34 is open to atmosphere through port'39, pipe 122, pipe 121, port 59, 57. The chamber between piston 36 and cylinder head 38' is also open to atmosphere through port 40,'pipe 120, port 60, to cavity 119 and port 57.` Consequently'spring 37 is the only Aforce that resists the force on the diaphragm 341 due to the action of the centrifuge, and the vehicle is limited as previouslyfex lained to a speed of, say, 10 miles per our. -A reservoir 124, used for a purpose to be pointed out later, is connected to pipe 121 by means of a pipe 123 and 'is therefore also under Yatmospheric pressure. k i y A To change from lowvspeed'vto vmedium speed, contact P is closed to energize'ramp Contact shoe 94 f les,y

cavity l119 and vport 108, and'contact P is vopened -to d ener.-y

gize ramp 109. If 'contact shoe v94. now

makes contact with the :energized ramp V108 v ilse ing contact 119 on car Wheel 2, wheel 2, and track rail 1 back to battery K. Thus electromagnet 80 is energized and operates double pin valve 68, so that air is admitted to the right hand side of piston 631 from port 84 of cylinder 5l, valve 70, passage 86, past ball check valve 88, pipe 90 and port 92. The left hand side of piston 631 and the right hand side of piston 62 areconnected to atmosphere through pipe 91, small passage 130, passage 87, and valve 7 3. While contact shoe 95 is on the. upper portion of ramp 109, trip 102 engages with valve stem 101 to open valve 103, thereby connecting the left hand side of piston 62 to atmosphere through port 55, pipe 107 and exhaust port 106 of valve 103. Since the area of piston 631 is greater than that of piston 110 the force acting on piston 631 is greater than that acting in opposition on piston 110, and as a result, pistons 631, 62and 110 and slide valve 56 are displaced to the left through the distance b. The new position of the slide valve 56 With respect to the ports of cylinder 51 I have shown in Fig. 2B. Port 60 is now uncovered and air pressure is admitted to cylinder 34 through port 60, pipe 120 and port 40 of cylinder 34, forcing piston 36 against stop 41. Thus spring 37 is compressed, and as explained above, the ve-v hicle may travel at a speed higher than before, say,20 miles per hour. As soon as contact shoe 95 leaves the higher ortion of ramp 109, valve 103 closes and air pressure passing through thev orifice 128 from cylinder 51 builds up pressure on the right hand side of piston 110 and in cylinder 53, pipes 107 and 126, pipe 126 now being closed at port 58 by valve 56. The forces tending to move valve 56 are now balanced, hence valve 56 remains in the position shown in Fig. 2B, Which I will call the medium speed lposition. When contact shoe 9i leaves ramp 108, valve 70 is again closed and valve 72 is opened, connecting the right hand side of piston 631 to atmosphere through port 92, pipe 90, small passage 129, passage 86 andvalve 72.V The purpose of the ball check valve 88 and the small passage 129 is toretard the rate of reduction of pressure to insure that the pressures on both sides of piston 110 will have equalized before the pressure of piston 631 against pistons 62 and 110 is removed. After ashort interval of time, therefore, the air pressure in chamber 53 will force pistons 62 and 631 back into the positions shown in Fig.. 2, whereas pistonA 110 remains in the.

medium s ed position. If, due to the vibration o the vehicle, valve 56 were grada allycaused totravel to the left, a dangerous condition wouldaris'e, for the valve would ultimately reach the high speed osition to be described below. To prevent t is, l provide valve 56 with a cavity 134:. Themas Leashes cavity 134: and port 57 and in -consequence,

the p ressure is diminished on the right side of plston 110, causing the latter to move hack to the medium speed position. Thus port 58 is again closed and pressure on the two sides of piston 110 equalized.

If nowI ramp 109 (which I will term the high speed ramp) is energized when it is engaged by shoe 95, current flows in the following circuit: from battery K', through circuit controller P', ramp 109, contact shoe 95, wire 131, energizing Winding 81a of magnet 81, wire 118, contact 119, wheel 2, rail l'to battery K. Thus magnet 81 is energized and actuates double pin `valve 69 to admit air to the right hand side of piston 62 from port 85 of cylinder 51, valve 71, passage 87, past ball check valve 89, pipe 91 `and port 93. While contact shoe 95 is on the upper portion of ramp 109, trip.102 engages valve stem 104 opening valve 103 f and allowing-air to exhaust from the chamenters cylinder 3i Deursen pistons 35 and 36,`

forcing piston 36 back against cylinder head 38, as explained above. Air ressure is now exerted directly vagainst the full area of the diaphragm and the speed of the vehicle may be increased to its highest allowable value, which l assumed to be 50 miles per hour. Reservoir 12,4 also is filled with air pressure. soon as Contact shoe 95 leaves the higher portion of ramp 109, valve 103 closes, and air pressure passing through the orice 128 from cylinder 51 builds up pressure on the right hand side of piston 110 and on the left hand side of piston 62 and in pipe 107 and 126 as before. Hence, slide valve 56 remains in 'the position shown in Fig. 2C. contact shoe 95 leaves ramp 109, magnet 81 is denergized andv double in valve 69 is returned to its ,normali position. Air gradually. exhausts from the right hand side of piston 62 through port 93, pipe 91, small passage 130, passage 87 and valve 73. After a shorty interval of time, therefore, the air pressure in chamber 53 will force piston 62 back into the position shown in Fig. 2, piston 110 remaining in its extreme left or speed position.

in t e high speed position, the vehicle are two ramp rails 108 and 109 placed paral- When.

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reaches a location in the track where there 1 lel to each other, lonly the mediums ed ramp 108 being energized and the igh speed ramp 109 denergized. Then as contact shoes 94 and 95 make contact with their respective ramps only magnet 80 is energized. Trip 102 then opens valve 103 and as previously explained, air pressure is exhausted from the left hand side of piston 62, pistons 631 and 62 are moved to the left through distance b, and piston '110 is moved to the rioht from its position at the fextreme left until it comes into contact'witli piston rod 66. Thus slide valve 56 is moved to the medium speed position, and it re-v mains there, whereas piston 62 and 631 are returned to the extreme right position, as previously explained. By moving to the medium speed position, slide valve 56 con-` nects port 59 to atmosphere by means of cavity 119 and port 125 which latter is an orifice of restricted area. The airin reservoir 124 and in cylinder 34 between pistons and 36 then ldischarges through orifice 125, at a predetermined rate, depending upon the relativeproportions of orifice and reservoir. 4As a result the pressure against diaphragm 341 is gradually reduced, and the speed limit imposed upon the vehicle by the control apparatus diminishes at a predetermined rate from the high speed.. limit to: the medium speed limit. Thus, if in "the above example the engineman reduces`v the speed of the vehicle from" 50 miles per,

hour to 20 miles per hour at-a rate of change"` l equal to or.

aterj than that determined bythe reservoir 12-1and orifice125,an auto- -matic application ofthe .brakes by the cony 35. trol a ,paratus will be avoided.,

' If t e speed lof-the v ehi le is not reduced,

the brakes "are applied automatically. They are applied at. once if the vehicle is travely Spe@ ing' at its highest speed, and are.v applied -after an intervalv of time when the speed of `the vehicle is less than 4the maximum, the l'length of this time being greater when the speed ofthe vehicle is low. l

If, while the slide valve 56 is inthe high d position or the medium speed po- [Sitiomthe vehicle passes two ramps -108 and 109 both of which are denergized, or one .yramp 109 which is denergized, neither "magnet 80 nor 81 is energized, but valve 103 is opened. Consequently air exhausts from cylinder 53 to atmosphere and the i valve 56 is moved to the low speed. position mosphere, thus removing allpressure from,

diaphragm 341'except that exerted by .the spring 3"(', so that the low speed (10 miles per hourinthecase assumed) is-,imposed by the speed controlling apparatus,l

Referring now to Fig. 3, I have here shown a railroad track, having track rails 1 and l1 divided .into sections, A, B, C, etc., by means of insulated joints 111. This track is equipped with a signaling system, preferably` one which is capable of giving three in ications, viz., proceed, caution and stop.' I have shown naling system usin SC, etc., of the t ree position type, although do notwish to 'limit myself to any articular type of'signal. The circuits by w ich these signals are controlled form no part of my invention, `hence I have omitted them to avoid unnecessary confusion. Ramps 109a and 109 track, one of the former being 'placed at approximately maximum braking distance in the rear of the entrance to each block, and

on the drawing a sigare located along thesemaphore signals SD, I

entrance end of each block. As here shown,

ramps 109a and 1095 are located at equal distances from the track rails, so that the contact shoe 95 of a trainVequipped as shown yin Figs. 1 and 2 makes contact with them successively as the train moves alongV the track.

y Circuit controllers PB, PC, PD, etc., roy vided for a. purpose to be pointed out be ow, ,areA operatively connected with the semaphore arms 112 of signals SB, SC, SD, ctc., respectively. Each circuit controller has, as hereshown, a contactfnger 138 operatively connected with the semaphore, a xed contact point 135 and a fixed contact strip 137. Batteries 1 KB, onefor each block. Onev terminal of each ybattery is connected to lthe track rail 1 of the preceding lblock section. by means of wire 115, the other terminal being connected to the ramps 109,5. and 109b by Wire 114, switch P, and wires 113 and 116, whenever contactnger 138`of/switch P is in such a position that it Y. will' make contact" with strip 137.

Suppose that block section D is occupied by a train V. Then `in the system of signalin which I have used for illustration, signa s SD, SC and SD will indicate stop caution and proceed respectively. lAccordingly a secondtrain V equipped with apparatus asshown -in Figs. 1 and 2 approaching block B inthe direction of the arrow, should be allowedl to enter that block at full speed. Ram 109b at' the entrance to block B is energize switch PD being closed because signal Sindicates proceed. Con' sequently current Hows from ramp 109b through the circuit on the train as described for Fig. 2 to the track rail 1f, 'and by the operation of apparatus described above, the

train is permitted to travel'at the highest speed, which I assumed to be 50 miles per our.

Since block C the signal indicates cau.

KC, etc., are provided tion and vsvvitch PC is closed, the ramps 109a and 109b 'adjacent the entrance of, this block are energized and the speed of the train ma continue to -be 50 miles per hour.

i 'ghe signal SD, however, stands at stop and switch PD is open. -Consequently ramp 109, braking distance in the rear of the entrance to block D, is denergized. As a'result the control apparatus on the train 1mposes a speed limit which gradually reduces from a maximum of 50 miles per hour to 10 miles per hour, and unless the speed or the train is reduced, the brakes are automatically applied so that under no condition'can the speed 'of the train exceed 10 miles per hour at ramp 109b at the entrance to block ,Dp Thus train V is prevented from passing stop signal SD at a speed in excess yof 10 miles er hour.

Suppose now tliat train V has moved out of block D and into block E by the time that train V reaches ramp 109b at the entrance to block D. Then signal SD does not indicate stop, but caution, Ramp 109b is energized and accordingly the train V mayresume full speed and 1t may contlnu'e vat this speed until it meets the next rail 109, when it must again reduce speed unless train V has left block E. t

The apparatus shown in Figs. 1 and2 1s particularl adapted for use in connection with a railway on which, owing to curves and grades, it is l.desirable to enforce at times a medium speed limit, such, for eX- ample, as 20 miles per hour. Such a condi-y tion is illustrated in Fig. 4, in which I have shown a railroad track divided into block sections G, H, etc., two of the block Fig. 3 connected ramp 109EL and 109h to hat? tery K are connected to the-ramps 108a and 108", so that these ramps are energized when the switch P is closed, but the corresponding ramps 109 and 109b are never energized.

Sup ose train V occupies block K. Then, with the control apparatus used in Fig. 3, a train V may be running at they speed of 50 miles an lhour when it reaches ramp 109 in the rear of the entrance to block K. But, on a down grade, the speed of the train V cannot be reduced from 50 to 10 miles per hour Within this distance, even were ramp 109a located a full block in the rear of the entrance to block K.

The modification of my system shown in Fig. 1 overcomes the above di'iiiculty. .At

the entrance to block H the ramp 109b isenergized and the vehicle may proceed, at high speed into block H in the direction of the arrow. The next block I should not be entered at this high speed, even though signal SI indicates proceed, because block I is on a down grade. Vhen the vehicle proceeds in block H and encounters ramps 108a and 109,of which only ramp rail -108a is energized, the control mechanlsm is operated as explained in the description of Fig. 2 and the speed limit of the train is gradually reduced to the medium speed limit, say 20 miles per hour. Unless the speed is gradually reduced as the train approaches block I, the brakes are applied automatically, so that at the entrance to block I the speed of the train is 20 miles per hour orv less.

The signal SJ at the entrance to block J 'indicates caution, consequently the ramps 'dicates stop. Therefore the ramps controlled by signal SK are not energized, and, unless the speed of the train has already been reduced, the brakes are applied automatically so that the tra-in is prevented from passing stop signal SK at a -speedin excess of l0 miles per hour.

If then train V proceeds out of block K, and has also passed out of block L by the time. train V reaches ramp 109 controlled by signal SL, this ramp is energized and the tram ,V may speed up again to itsmaximum speed of 50 miles per hour.

Thus my apparatus enforces a continuous speed limit, the limit over any section of track being lthe maximum safe speed under the particular condition of track and block.

In Fig. 5 I have shown a modification of the electropneumatic control apparatus of Fig. 2. In this modification I employ but a singlefco'ntact` shoe 95 and lcorrespnding magnet 81 and pin v lve 69. Cylinder'll Which in Fig. 2 is co nected to-the second pin valve is in this modication connected to pipe 121 by means of a pipe 300 and port 301. By this means piston 631 is held in the extreme left position, in other Words, the valve 56 is held or moved to the medium speed position When the pressure on the right hand side of piston 631 is greater than the pressure on th left hand side of piston 62. I assume furt ermore that the tension of spring 37 of Fig. 1 is such that it exerts no force against diaphragm 341 unless piston 36 isforced to the left due to air pressure in pipe 120, so that when the air pressure is exhausted from both pipes 120 and 121 the brakes will be applied automatically so that reservoir 61 supplies air pressure to cylinder 51, and all the passages open thereto, z'. e., to pipes 121 and 120 through ports 60 and 59 and to cylinder 53 and pipes 107 and 126 through orifice 128 in piston 110. Furthermore, pistons 62 and 631 are displaced to the left through distance b because air pressure has entered cylinder 54 through port 301. The train may therefore proceed under the maximum speed limit. A

Suppose now that the train encounters a .denergi'zed ramp 109. Thenvalve 103' is L 95and air` pressure exhausts throughpas-` opened by trip 102 carried by Contact shoe sages 55-and 107 and exhaust port 106 of valve 103 to atmosphere. Thus the pressure on the right side of piston 110 is lowered and piston 110'and valve 56 are moved to the.

rifght into engagement with piston rod v66 o iston 62, z'. e. into the position indicated in ig.v 2B. Thereby port 59 is opened to' cavity 119 of slide valve 56 which communicates with atmosphere through orifice 125.

`Consequently the air pressure in reservoir 124 and cylinder 34 is" gradually reduced causin a gradual decrease 'in the speed limit rom the highest value, which I assume as miles per hour, to thelowest of 10 miles per hour.. Since'the connection to atmosphere through pipe 107 andvalve 103 is closed as soon as the train has passed beyond ramp 109, air flows from cylinder 51- `through orifice 1,28 of piston -110 into cylinder 52 and through passage 55 into cylinder 53, thereby developing full pressure on the left hand side of piston 62. But since the right hand side of piston 631 is' conhausted from pipe 107 causing piston 110 to be forced to the right into the position nected to pipe l121, in which the air pressure is decreasing, pistons 62 and 631 are forced to the sright.- Valve 56 remains in the position shown in Fig. 2B, because the pressures on thetwo sides of piston 110 are equalized. Suppose -now that, the train encounters second denergized ramp 109. Then valve 103 is again opened, and air pressure is'exshown in Fig. 24 due to the air pressure in cylinder 51. Now valve 56 connects ports 59' and 60 to atmosphere throughcavity 119 and port 57. Piston 36 of cylinder 34 is forced to the right by the expansion of spring 37 andsince the diaphragm is now unsupported by any force on its right, the vehicle is brought to anabsolute Stop'.

If ramp 109 is energized, magnet 81 operates double pin valve 69 so as to allow air pressure from cylinder 51 to enter cylinder through pipe 91 andport 93. As a relt, piston 62 is forced to its left extreme position and moves slide valve 56 to the p0- sition indicated in Fig. 2. Air pressure now enters pipes 121 and 1.20 restoring all the apparatus to the original position shown in Fig. 5 and the speed of the Vehicle may again be brought up to the maximum value.

In Fig. 6 I have shown a modification of the control system for the apparatus shown in Fig. 1. The form shown in this modification is `in a sense an electromechanical equivalent of thepiston slide valve apparatus shown in Fig 2. The apparatus shown in Fig. 6 is also so arranged that it is adapted for the control of trains consisting of a number of similar cars, each of which is equipped with the apparatus` shown in Figs. 1 and 6. Four wires 15o, 151, 152, 153 are provided for each car, each wire being connected to the corresponding wires of the adjacentcars by means of couplers v154.l A battery 155 is permanently vconnected to Wires 150 and 151 by means of wires 156 `and,157. Contact shoes 162a and 162b are located -at diagonally opposite corners of the jvehicle so` that one of the contact, shoes 162 and 162bis always in position to engage aramp- 109 a number of which l bridge contact ,points 168-169 and 170-171- respectively. These circuit controllers lare biased normally to closed position by means of springs 172, and opened by means of trips 173 adapted to engage rods 167 during the upper portion of their stroke. Each car is provided Withv two relays 158 and 159 responsive to alternating current and with two `relays 160 and161 responsive to direct current.l The energizing circuits of relays 158 and 159 are a'rtlyon the-car and are partly on the roadside. Thus relay 158 is connected to contact shoes 16.2a and 162b by wires 218 andf188 respectively, and to a sliding con-4 tactf1'19 onjacar Iwheel by means of Wire 211.v Similarly, relayf159 is connected to contact shoe'163'by means of wire 210 and to' sliding contact 119" by wire 211.

The roadside-part of the energizing circuits of relays 158 and 159 will be described in detail hereinafter. Suiice it nowto point out that ramp 108 or 109 may be energized `by connecting one terminal of the secondary 4 of a transformer T or T to a running rail 1 and connecting the other Aterminal of the secondary oftransformer T or T' through a circuit controller P or P to ramp 108 ory 109. Hence relays 158..or 159 are energized as long as either contact shoes 162a or 162", or 163 make contact with an energized ramp 109 or 108 respectively. Relay 160'may be energized by current flowing in the followingcircuit: from battery 155, through wires 156, 150 and 197, contact 189 of relay 158,

,- circuit is broken by openin controller 164a or 164",

wires 192, 151 and 157 to battery 155. Thus" relay 160 lremains energized until its stick either circuit Simi arly, relay 161 .is energized by current flowing in the circuit: from battery 155 through wires-156,` 150 and 197, contact 212 of relay 159,' wire 213, relay 161, wires 192, 151 and 157 to batrtery 155. When relay 161 i's energized it is I signal lights held so by current flowing in its stick circuit: fromibattery155, wires 156, 150 and 505, contact bar 165 of circuit controller 164, wire 214, contact bar 165 of' circuit controller164", wire 208, contact 202 of relay 161, relay161 wires 192, 151 and 157 to battery 155.

either circuit controller 164a or 164". y p The cab of each car is provided with three R Y, G, colored preferably red,v yellow and green, respectively. Red

lamp R is energized through the circuit:

from battery 155, wires 156, 150, 197 and 198, back contact 205 of relay 161, wire 199, back contact 196 of relay 160, wire. 200, red lamp .wires 192, 151 and 157 tobattery 155. lThus red lamp R is displayed. when' both relays 160 and 161 are denergized. Green lamp G -is energized by current flowing through the following circuit: from battery 155, wires 156, 150, 197 and 198, back contact 205 of relay 161, wire 199, -front contact 195 of relay160, rwire 202, green lamp G,

wires 192, 151 and 157 to' battery 155. Henceya green light isdisplayed when relay 160 is energized and relay 161 is deepergized. The circuit for yellow lamp Y is as follows: fromY battery 155, through wires 15e, 15o, 197-and 198, front Contact 204 of relay 161, wire 215 yellow lamp Y, wires 192, 151 and157 to rhus relay 161 remains ener- ,gized untilv its sticlr-eircuit is opened at battery 155. Therefore,

meuse@ a yellow light is displayed whenrelay 161 is energized. From the above arrangement of circuits it is seen that only one light can be displayed at a time.

Magnets 80 and 81 operate dou'ble pin valves 68 and 69 in the manner described in connection with Fig. 2. The energizing cir.- cuit of magnet 81 is as follows: from. battery 155, wiresv156, 150, 197 and 198, back contact 205 of relay 161, wire 199, front Contact 195 of relay 160, wire 202, energizing winding 81a of magnet 81, wires 225, 192, 151 and 157 to battery 55.4 Therefore, magnet 81 is energized only when relay 161 is delenergized and relay 160 is energized. The

energizing circuit of magnet 80 is as fol lows: from battery 155, wires 156, 150, 197

and 198, front contact 204 of relay 161, wire 215, winding 80 of magnet 80, wires 192, 151 and 157 to battery 155'.. Hence, magnet 80 is energizedwhenrelay 161 is energized. It is 'evident from the above vthat magnets 80 and `81 cannot be energized simultaneously. When magnet 80 is denergized, spring 82 holds valve 72 open thus connecting pipe 120, which leads to port 40 of cylinder 34 in Fig.-1, to atmosphere. When magnet 80 is energized, up er valve 72 is closed and lower valvey 70 1s opened, thus 'admitting air pressure from mam reservoir 61 through pipe 181, port 84, valve 70 to' pipe 120 leading to the right hand side of piston 36 of Fig. 1. Similarly when mag` net 81 isdenergized, pipe 121, which is connected to pipes 122 and 123 in Fig.l1, is

openedato atmosphere, and when magnet 81 is' energized, pipe' 121 is connected to main reservoir 61. l

In addition tothe cab-signal lights I provide a pressure g 185, which is connected to pipe 121 to indicate the pressure therein. Since the pressure in pipe 121 has a ydeiinite relation to the speed limit imposed upon the vehicle by the control magnet 81, the res sure gage may be calibrated empirical y in terms of the permissive speed of the vehicle. Not being ccnnctexl to pipe 120, this pressure gage does not indicate the variation ofl speed imit imposed upon the vehicle due to the control effected by .the action of magnet 80. j

To explain the operation of this forni of my train control apparatus, assume that a train of one or more cars, each of which isv equipped with the apparatus shown in Figs. 1 and 6, travels alig the track rails one of Which-is shown on ig. 6 and is designated by reference character 1. Assume furthermore that all arts of the apparatus are in the positions s own in Fig. 6. Then all relays are denergized, consequently magnets .80 and 81 are denergized, their circuits being broken at contacts 204 and 195 of relays 161 and 160 respectively. Hence, atmospheric pressure exists in pipes 120 and 121,

iis

For that reason the only force opposing the force exerted on diaphragm 341 due to the action of the centrifugal governor 4 is that exertedV by spring 3T. As a result. the low speed limitI of 10 miles per hour is imposed on the car or train as explained hereinbefore. The pressure gage 185 indicates therefore atmospheric pressure in pipe 121, which may be marked 10 miles per hour on the scale. Red lamp R is illuminated, its circuit being completed through the back contacts 205 and 196 of relays 161 and 160.

Assume now that the train encounters an energized ramp 109. As either contact shoe 162b or 162a of the first car of the train engages the ramp, alterna-ting current flows in the energizing circuit of relay 158, which circuit is from secondary of transformer T through contact P', wire 187, contact 109" 162, or 109-162", wire 218 01'188, relay 158, Wire 211, axle 119, Wheel 2, rail 1, Wire 186, to secondary of transformer T. The contacts of relay 158 are therefore closed. Contact 189 of relay 158 closes the energizing circuit of relay 160, which therefore becomes energized and closes its front contacts. As a result magnet 81'is energized, its circuit being closed at front Contact 195 of relay 160 and back contact 205 of relay 161. and in attracting its armature it opens lower Vvalve 71 and closes upper Valve 7 3 of double pin valve 69. Air pressure enters pipe 121 from reservoir 61 and flows into reservoir 124 and cylinder 34 of Fig. 1, and thereby cutting in the high speed limit on the first car. The rise in pressure in pipe 121 is indicated by pressure gage 185. The circontact 195 of relay cuit for green lamp G- is closed through front 205 of relay 161, so that a green light is displayed in the cab, the circuit for red lamp R being broke-n at contact 196 of relay 160.

Since as previously stated each car of the train is to be equipped with the speed control apparatus, it is obviously necessary to apply the high speed control on all cars of the train in order to permit the train to resume full speed. Tt is also desirable, -in order to permit 'the train to get under Way Without delay, and in order that `the cab signal and speed limit indicator on the first car will correctly indicate conditions on the entire train, that the high speed control on the following cars be applied simultaneously with that on the first car, or in other words, that the relays 160 on each car of the train be energized at the same time the relay 160 of the first car is energized` due to the energization of relay 158 of the rstcar from an energized ramp 109. This is accomplished as follows:

When front contact 190 of relay 158 closes, battery 155 is connected to train Wire 152 through the connection; from .battery 160 and back contact' relay 160, energizing Winding of relay 160,

wires 192. 151 and 15T to battery 155.. The

.contact finger 221 of each relay 160 is of such construction that front contact 193 closes before back contact 194 opens. As soon as front contact 193 is closed, rela 160 is held energized through the stick circuit traced hereinbefore. With relay 160 of everycar energized, magnet 81 of each'car is energized, hence, the high speed limit of 50 miles per hour is applied to the Whole train.

Since the speed control equipment on each car of the train is identical, it is evident that if the ramp 109 is dener'gized when passed by the first car and is energized at any time before it is passed by the last car of the train, the oar Whose contact shoe is in engagement with the ramp at the time itv becomes energized will serve the function of v the first ca r7 described in the preceding paragraph, to simultaneously apply .the high speed control on all cars of the 'tram to permit an immediate acceleration lto .full speed. This is of great advantage' 1n 1.11- creasing the -trafiic capacity, as it permits a train which has been held down to a low speed due to unfavorabie conditions ahead, to immediately resume full speed upon the closing of circuit controller 1 due to the removal of the unfavorable' condition provided some car of the train is in engagement with a ramp, and in fact permits continuous control of the train by circuits located in the roadway, Without the employment of a continuous roadside contact rail, provided that the successive ramps are spaced a distance apart not greater than the length of the trains.

For another illustration of the operation of the above form of mysystem of train control, assume that the first car of the train next encounters a ramp 109 which has been. denergized by opening the corresponding switch P. Then relay 158 is, of course, not energized, but the stick circuit of relay 160 is broken by circuit controller 164a or 164". As a result relay 160 opens its front contacts, thereby breaking the energizlng circuit ofl magnet 81 at contact 195. Consequently spring 83 closes lower valve 71 and opens upper valve 73 of double pin valve 69. Pipe 121 is therefore open to atmosphere and the air pressure in cylinder 34 force exerted against diaphragm 341 is gradually diminished and the speed limit is gradually decreased from 50 miles per hour to 10 miles er hour. This is indicated by gage 185. (Breen lamp G, thev circuit of which is broken at front contact 195 of relay 160, is extinguished, and the red lamp R is displayed, because its circuit is closed by back contact 196 of relay 160.

In the case of a train of more than one car, this process is repeated 'for every car of the train' as it passes the ramp 109.

Assume that the first car of the train next encounters an energized ramp 108. Con tact shoe 163 engages this ramp causing alternating current to flow in the energizing'v circuit of relay 159, which circuit is from secondary of transformer T,'through contact l?, wire 211, contact 108-163, wire 210, relay '159, wire 211, thence through the axle, wheel and rail l to transformer T. The front contacts of relay 159 are therefore closed. The energizing circuit vof rela 161 is closed at contact 212 of relay 159, ence relay 161 closes its front contacts. Contacts 204 of relay 161 closes the energizing circuit of magnet 80 which therefore attracts its armature thereby opening lower valve 70 and closing upper valve 72 of double pin valve 68. Thus air pressure is admitted to pipe 120 from reservoir 61 and byexerting pressure against piston 36 in cylinder 34 of Fig. 1 it compresses spring 37. Now piston 35 of cylinder 34 presses against diaphragm 341 with a pressure corresponding to 'the medium speed limit. IThe' circuit ,for red lamp R is broken at back contact 205 of relay 161 Aand the circuit for yellow lamp Y is closed at front contact 204 ofA relay 161. Consequently, the red light is extinguished and the yellow light is displayed.

Relay 159 also closed contact 222 to vener-' gize train wire 153 by the following circuit: from battery 155, wires 156, 150 and 197,

contact 222 of relay 159, wire 223 to" wirev 153. By nleans ofcouplers 154, wire 153 of every' car of the train is energized. Hence on each car of the train, the circuit is ccmpleted from wire 153 to wire 223, back con' tact 203 of relays 161, energizing winding of relay 161, wires 192, 4151 and 157 to battery 155. Contact finger 232 of relay 1611' is constructed so as to close the front contact 202 before it opensback contact 203. As a result each relay 161 remains energized through its stick circuit once it has been Aenergized.. `'lhus magnets 80 of 'each car o the train are energized simultaneously. Similarly, magnets 80 of each car of the train will be energized simultaneously if ramp 108 is-denergized when passed by the first car of the tra'in, but isY energized byclosin circuit controller l? before it `is passe 'f by the last. car of the train.,

`net 80 as described hereinbefore.

If now the first car ofthe train simultaneously encounters ramps 108 and 109 both of which are denergized, or encounters a deenergized ramp 109 alone, neither relay 158 nor 159 is energized but the stick circuit of relay 161 is broken by circuit controller 164 or 164b and, asv a result, rela y 161 is denergized. Consequently, magnet 80 is denergized, its circuit being broken at contact 204: of relay 161. Air pressure inY pipe 120 and behind piston 36 ol; cylinder 34 is exhausted through upper valve 7 2 of double pin valve 68, allowing spring 37 to expand. As a result the low speed limit is imposed on the car. The circuit for the yellow lamp Y is broken at contact 204 and the circuit for red lamp R is closed at contact 205 of relay 161. Hence the yellow light is extinguished and-the red light is displayed. This process is repeated by the apparatus on each car of lay 161 o ens at back contact 205 the .cir-- cuit of re lamp R and closes at contact 204 the circuit for the yellow lamp Y and mag- Magnet ,ca'uses air pressure from cylinder 61 to enter pipe 120 leading to port 40 of cylinder 34, so that piston 36 is moved to.I the left 'against stop 41. Circuit controller 164a or 164 opens the stick circuit of relay 160,l

which therefore breaks the circuit for ,magnet 81 at contact 195. As a result pipe 121 is opened to atmosphere at valve 7 3 and the pressure in reservoir 124 and cylinder 34 gradually drops, so that the speed limit is gradually reduced fromv the high to the medium value and the yellow lamp Y is displayed. This process is repeated by the apparatus on each car of the train as the contact shoes of each car encounter the denergized ramp 109 and the energized ramp 108,

and asn a result the speed limit is. changed from the high speed to the medium speedf on each car of the train in succession.

When theapparatus shown in Fig. 6 is employed on'each car of a train, it is apparent that Aif the ramp 109 were located at the entrance of a block and were sok controlled as to be denergized upon the entrance of af train into the block, the rst car or twovof the train might receive a procd indication from the ramp but the last cars would receive a stop indication. owing to the denergization of the ramp by the foriasv ward part of the train, and the train would thus be brought to a stop even though trafiic conditions were such that it could properly proceed at full speed. The control of the ramps must therefore'be such that each ramp which is energized when encountered by a train continues to be energized until the entire train has passed over the ramp. 'One manner of securing such control is illustrated in Fig. 7, in which l, 1 designate' the track rails of a. railroad track, one of which rails 1 is divided by means of insulated joints 111 into block sections N, 0,1?, etc., each of which is preceded by a preliminary section O, P', etc. Transformers T0, TP, etc., the secondary of each of which is divided into a number/of sections afb, c, d, are provided, one for each block, the" primary of each transformer being Connected with a source of alternating signaling current not shown in the drawing. Each track section is equipped with a track circuit. Thus the track circuit for section O consists of a source of electrical potential, which have shown as section b of transformer TP and is' connected to the track rails by Wires 261 and 263, the track rails l and 1', and a relay 2510 which is connected to the rails 1 and 1 by means of -.Wires 269 and 270. Similarly preliminary section O is connected at one end to coil c of transformer T0 by Wires 260 and 261 and is connected to a relay 2500 by Wires 267 and 268. Each block section is also providedwith a line relay 2520, 252", etc., which has an energizing circuit and a holding circuit. rlhe energizing circuit of relay 2520, for example,

is 2 from section l of transformer T0, throughwire 265, contact 258 of relay 251, wires 285 and 272, relay 2520, Wires 271, 273 and 266 to transformer T0. Hence relay 252o is picked up when relay 2510 is energized. The stick circuit of relay 2520 is asvfollows: from section d of transformer T0, through wires 265 and ,283, contact 256 of relay 2520, Wire 284, back contact 255 of relay 2500, Wire 272, relay 2520, wires 271. 273 and 266 to section d of transformer T0. Therefore, relay 2520 remains energized through its stick circuit, when relay 2510 opens, provided back contact 255 of relay 2500 has previously been closed. provide', furthermore, other line relays 2530, 2531, etc., one for each block Relay 2530 may be energized former TP, throughA wire 265, contact 258 of relay 251", Wire 285, contact 254 of' relay 2,50?, Wirev 281, relay 2530, wires 280, 271, 273 andV 266 to` section a? of transformer TP. Hence relay 2530 is energized if the front contacts of relay 250x and 251p are both closed. A ramp 109 which may at times befenergized is located in each auxiliary section' `O, Pf, etc. Ramp 109"l of section 0 for energized ramp 109", current flows from ramp 109a through the apparatus on the 75 train to rail 1 and from there by means of wire 261 back to section a of transformer T0.

lojdescribe the operation of this -system of train control apparatus, assume no train 30 on the track. Then, referring particularly to vblock section OO, relays 2500, 2510` 2520 and 2530 are all energized. Ramp 109a is energized because the front contacts of relays 2520 and 2530 are closed. If now a train equipped vwith the speed control apparatus described hereinbefore, enters preliminary section Of from block section N it opens relay 2500 which closes at back contact255 the stick circuit of 'relay 2520. As- 90 the train encounters ramp 109n it receives a proceed lindication in the cab due to the operation of the apparatus on the train or car, as described hereinbefore, and it may proceed under its high speed limit. Upon entering section (l, relay 2510 is denergized i and breaks at contact 258 the pick-up circuit ot' relay 252-O but this relay does not open; because its stick circuit is closed throughback contact 255 of relay 2500. .100

-Thcrefore ramp 109l remains energized as long as any part of the train is in preliminary section O. As the train leaves this preliminary section, relay 250o is again energized and opens at contact 255 the stick 105 circuit of relay 25,20, which is therefore detioned train proceeds through section O and enters auxiliary section P it denergizes relay 250". -causing it to open at contact 254 the energizing circuit of relay 2530, which therefore opens its Contact 259. At ramp 109a in auxiliary section P the car or train receives a proceed indication and may therefore pass into section P at full speed. Relay 2511 is denergized and opens at contact 258 the pick-up circuit or relay 252?, but as explained .hereinbefore relay 252P remains energizedy through its stick circuit lclosed at back contact 255 of relay`250f'. -Hence ramp 109B. remains energized as long 125 as part of the train isiin'section P. As it leavessection'P `relay 25.0P is energized and breaks at back contact 255 the stick circuit of relay 252?, which is therefore Adeneigired and breaks at contact 257 the connection of ramp 1091 to transformer TP. Hence ramp 109l is denergized as soon as the rear of the train is past. l

lhen the train leaves block section P completely, relay 251P is again energized and closes at contact 258 the circuit for relay 2530 of the preceding section. Relay 2520 having already been energized as the train left section (i), the circuit for ramp 109 of section O is again completed, so that if a following train makes contact with this ramp it will receive a proceed7 indication.

Thus the train is governed by the condition of the second block in advance provided the first block in advance is unoccupied at the time the train enters it, while if the train enters an occupied block, it is governed solely by the condition of this block, irrespecti ve of the condition of the block in advance of the occupied block. If two blocks ahead of the train are unoccupied a green light is displayed in the cab and the high speed limit is applied, but if the second block ahead is occupied, a red light is displayed and the speed limit is gradually reduced to the low value at the entrance to the occupied block, which may be then entered under control.

Fig. 8 shows a modification of the roadside apparatus described in Fig. 7 for use on curves and grades in the same way as Fig. 1 is a modification of the circuits of Fig. 3 for the same purpose. rThe modification consist/s of the addition of ramps 108a located between the tracks adjacent ramps 1.09". The ramps 108a may be energized through the same circuits as ramps 109a of Fig. 5, but ramps 109' have no electrical connections. By means of ramps 108a the medium speed limit may be applied in the same way as described for Fig. 3. l

The maximum traiic capacity is secured when the roadside apparatus shown in Figs. 7 and 8 is used in connection with trains made up of several cars each of which is equipped with the control apparatus shown in Figs. 1 and 6 and which are connected.

electrically by means of couplers 154, so that the train Wires' are connected in series throughout the length of the train. The length of the blocks is then preferably such that the distance between consecutive ramps is less than the length of each train, so that the train is always in connection with one ramp. Assume that in Fig. 7. a train A occupies block P and that a following train B is about to enter preliminary section 0. The first car of train B engages ram 109a causing a red light to be displayed 1n the (ab, showing that block P is occupied, and denergizingl the high speed control so that the permissive speed will be reduced to the lon7 speed value before the train reaches same time.

the entrance to block P. Suppose that before all of train B has passed ramp 109 of block O that train A leaves block l thereby renergizing ramp 109 of block O. Since one of the cars of train B is in engagement with ramp 109, the' control apparatus on that car is energized to re-apply the high speed limit, and at the same time train wire 152 is energized to simultaneously apply the` high speed limit on all cars of the train, displaying a green light in thecab of the first car, permitting full speed to be immediately resumed for the remainder of block O.

Assume that on the other hand the train B had passed beyond ramp 109a of block O before train A leaves block P. Then if train A leaves block P the control apparatus on train B will be rencrgized to apply the high speed control and to display the green light when train B reaches ramp 109", which is preferably located near the exit end of block 0 and which is connected to ramp 109a of block O by wire 9.7 9. Thus the train B can now enter block P in the rear of an occupied block under the same condition, namely, with the Speed limit initially at the high speed value, as it previously entered the block O in the rear of the occupied block P.. As train B enters blocks P. ramp 109" becomes denergized, giving the same indica-V tion as ramp 109" of block P', because track relay 251P is denergized, which opens the circuit of relay 2530 at contact 258, and relay 2530 opens the circuit of ramp 109" at contact Q59.

Assume now that block P is unoccupied, so that ramp 109"L of block P is energized, and that the train B entering block P is of sunicient length to engage ramp 109" of block O and ramp 109n of block P at the Then the ramp 109" as previously explained, will be denergized because track relay Q51P is denergized, butA it will not affect the control of the train, which will 11u be controlled solely by the ramp 109a of block P', because' the relay 160 on the car in. engagement with the denergized ramp 109b will be renergized through train wire 152 from the relay 158 of the car in engage- 11,5

ment with ramp 109, although its holding A coupled together trains following the first train in the same block are held at the low speed limit.

Referring now to Fig. V9, I have here .180

shown a modification of the apparatus of Fig. 6. This modiication differs from the apparatus of Fig. 6 in the following respects: Contact shoe 163 with its corresponding alternating current relay 159 and the medium s eed control wire 153 ofFig. 6 are replaced Ey a contact 296 which is controlled by air pressure acting on one side of a diaphragm 295 in opposition to a spring 293 acting on a piston 294 on the other side of the diaphragm.. Air pressure is brought to the underside of diaphragm 295 by means of a pipe 292 connected to the pipe 121 which is connected to port 39Yof cylinder 34 in Fig. 1. When the pressure in pipe 121 is at or'above a certain value predetermined b y the adjustment of spring 293, contact 296 is closed due to the upward displacement of piston 294, but whenthe pressure falls below that value, contact 296. opens by action of the spring. The pick-up circuit of relay 161 ispassed through contact 296, so that i this circuit is as follows: fromv battery 155,

`through wires 156, 150, 197 and 298, contact 296, wire 297, relay 161, wires 192 151 and 157 to battery 155. Hence the pick-up circuit. of relay 161 is closed as long as air pressure above the predetermined value exists iii pipe121. The circuit for red light R is: from battery 155, through Wires L56,

` 150, 197 and 299, back contact 196 of relay 160, wire 300, back contact 205 of relay 161, wire 200, lamp R, wires 192, 151 and 157 to battery 155. Hence'red light R is displayed when both relays 160 and 161 are denergized. The circuit for yellow light Y and magnet 80 is: `from battery 155, through wires156, 150, 197 and 299, back contact 196 of relay 160, Wire 300, front contact 204 of relay 161, wire 215, lamp Y and winding 80 of magnet 80 in multiple, Wires 192, 151 aud 157 to battery 155. vHence yellow light Y is displayed. and magnet 80 is energized i when relay 161 isenergized and relay 160 is denergized. The circuit for green light Gr and magnet 81 is: from battery 155, through Wires 156, 150, 197 and 299, front contact 195 of relay 160, wire 202, lamp G and winding 81a of magnet 81 in multiple, wires 192, 151 and 157 to battery 155. Hence when relay 160 is energized green light G is displayed and magnet 81 is energized.

When'the apparatus shown in Fi 9 is used in connection with that shown 1n Fig. 1,-the tension of spring 37 in Fig. 1 is such that it exerts no pressure against da hragm 341 unless piston 36 lis forced to the liift, because of air pressure in pipe 120, so that if the air pressure is exhausted from both pipes 120 and 121 the brakes will be applied automatically if the train is run at any speed. When the spring is compressed due to air pressure in pipe 120 the speed limit is increased to a low value, as for example to 10 miles per hour. Since the high speed ,I To explain the operation of this modification of my system of train control, assume Fig. 9, that is, that both relays 160 and l161 are energized. The1,`as explained hereinbefore, green light G is displayed, magnet 81 is energized and. air' pressure exists in. pipe 121 and the adjoining passages, so that the high speed limit is applied. Assume now that the train reaches' a denergized ramp 109, so that the stick circuits of relays 160 and 161 are broken at contact 164a or 1641. Relay 160 is denergized, but relay 161 remains energized, its circuit being closed at the pneumatioally controlled contact 296. As a result,yel1ow light Y is displayed, magnet 80 is energized and magnet 81 is denergized, so that the pressure in pipe 121 escapes through valve port 73 which is restricted in area so that the reduction of pressure is gradual. As the air pressure in pipe 121 gradually decreases, the speed limit is gradually reduced. Contact 296 opens as soon asthe air pressure in pipe 121 drops below the predetermined value,

but in the meantime the Contact shoe has the apparatus is in the conditon shown in circuit for relay 161 is closed through the i shoe operated contact and this relay remains energized. Piston 36 is moved 'against stop 41 due to air pressure in pipe e 120, compressing the spring 37, so that t train may proceed under the low speed limit of 10 miles per hour until a second ramp 109 is encountered. If this ramp is denergized,

the stick circuit of relay 161 is opened at contact 164a or 1641, and, contact 296 in the pick-up circuitof that relay being open, relay 161 is denergized and opens at-contact 204 the circuit for magnet 80 and yellow light Y. Air pressure is exhausted from pipe 120 removing the tension from spring 37. As explained hereinbefore, this causes the train to come to an` absolute stop. Red lightR is displayed, its circuit being closed at contact 205 of relay 161.

The train cannot' proceed until it receives a proceed indication by the energizatiou of the ramp 109 at which it came to a stop. If ramp 109 is energized, relay 158 is lenergized and closes the circuit for relay 160 at contact 189. Relay 160 closes at contact 195 the circuits of green light G and magnet 80.

Therefore the green light G is displayed and air pressure is admitted to pipes 121 and 292. and contact 296 is again closed; thereupon relay 161 is energized and closes itscontacts 202 and 204. -Thusfall the 'apparatus has 

